Optifine does tons of neat stuff, but it does not work for everyone. For some people it even causes problems.
There used to be at least two shader mods apart from optifine.
I would love a simple clean forge mod, where all it does is make all (or some) existing shaders work. This might be a huge job, or it might even be nearly impossible, I have no idea.
Examples of shaders
Alternately: If support for all shader packs is not possible, I would be totally happy with just a standalone shader mod. So you install it, it has very small simple shader effects hardcoded and thats it.